[OSM-talk] the coast and colour of the sea

[Paul]

Just looking at the coast of Australia and its very hard to tell which
is sea and land using the main default OSM map.
eg
http://www.openstreetmap.org/?lat=-36.2991&lon=150.1429&zoom=12&layers=B0F

is there something apart from the coastline which colours the sea or is
this a function of  Mapnik?
I note the OSMrender shows the sea it a very different contrast.

Paul